Workshopband als PDF - Mpc.belwue.de

MPC-WORKSHOP FEBRUAR 2013
Headless Android Systems for
Industrial Automation and Control
Aneeque Hassan, Axel Sikora, Dominique-Stephan Kunz, David Eberlein
Abstract—Android is an operating system which
was developed for use in smart mobile phones and
is the current leader in this market. A lot of efforts
are being spent to make Android available to the
embedded world, as well. Many embedded systems
do not have a local GUI and are therefore called
headless devices. This paper presents the results of
an analysis of the general suitability of Android in
headless embedded systems and ponders the advantages
and disadvantages. It focuses on the
hardware related issues, i.e. to what extent Android
supports hardware peripherals normally
used in embedded systems.
Index Terms—Android, Accessory Development
Kit (ADK), Android Open Source Project (AOSP),
Asynchronous Shared Memory (Ashmem), Microcontrollers
(MCUs).
I. INTRODUCTION
Android is an operating system for mobile devices
developed by the Open Handset Alliance (OHA).
Android enjoys being the market leader in the field of
smart phones with a market share of more than 70 %
[1]. Android is based on the Linux kernel. So the
question arises if there are any additional benefits in
using Android instead of Linux for applications outside
the smart phone or tablet world, i.e. for applications
from industrial, process, or building automation.
The objective of this project was to discuss the suitability,
i.e. the advantages and disadvantages of Android
for headless systems in industrial automation. In
the projected case, the anticipated end product was a
system without a local user interface, but with the
option to add a GUI for a certain percentage of the
applications. This paper will only cover the use case
that all applications are Android based and there are
no Linux applications. A heterogeneous system (Android
and Linux applications) would need further
investigations.
Aneeque Hassan, ahassan@stud.hs-offenburg.de, and Axel Sikora,
axel.sikora@hs-offenburg.de, are with Hochschule Offenburg,
Badstraße 24, D77652 Offenburg.
Dominique-Stephan Kunz, dominique.kunz@ch.sauter-bc.com,
and David Eberlein, david.eberlein@ch.sauter-bc.com, are with Fr.
Sauter AG, Im Surinam 55, CH4058 Basel.
Figure 1: Architecture of Android [2].
A basic question in this context is the support for
external hardware peripherals. Specifically built for
smart phones Android does not need to provide generic
support for external interfaces like SPI, UART,
GPIO or similar peripherals as opposed to "normal"
embedded systems.
In this paper first the architecture of Android is presented
in ch. II and the concept of headless Android is
introduced in ch. III. Then the used baseboard is shortly
presented in ch. IV. The extension of Android based
systems with additional local hardware interfaces was
the most important part of the project. The mechanism
of hardware support in Android is discussed in ch. V.
Then the timing results of the test setup are presented
in detail in ch. VII and ch. VIII. The report is concluded
by giving an opinion based on the findings during
the project.
II. ANDROID ARCHITECTURE
Android is based on the Linux kernel, a number of
software libraries written in 'C', a Java-like virtual
machine for the execution of application code, and a
full suite of mobile phone applications [3]. Fig. 1
shows an overview of the Android architecture.
67